SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e349879d9b1676c9b3fa491727652972def78e20d6a1a05ea983944127eb3535' 
  AND token = 'NKfuWXYY+7gavGKirRAOAyc2Bx4e4FIlkWnHL7l+pds=' 
  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"
    }
  }
}