SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5f35a25491fe4cac4279955c90320e86aed4bdbfaf3cf95ed31fdebb14b4e1b' 
  AND token = 'F7g7jldD25lwOmRRmjnE73fETBhNHPj81AznVRsy/oQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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