SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bc5b86340dcf170b13eb60f151c07582a47352bea732aaff24e612bf3cb55fe' 
  AND token = 'jI7s6E+Ir57w4j0OubY3KRhtaDyZhKqDKtb00RZsmBo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}