SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e2ebddd7437f6d431065664feb405c5365f9b1e1b64357bbdd4f3cc88c0435f' 
  AND token = 'tb/i9SXO6iKbn7D0xDQ6wkNtOjG0UKbH3SigxvZVfPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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