SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51d2fce52ecc45fdd15e251f69d7a47b10d31453751821bddec381029446d0f3' 
  AND token = '9dxJdcQZu5fme//IN2WChuxNRhX5C5CvEL3Euy3QW1Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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