SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6db77d82d329cbb901e1c34dd7d503ecf085ad3938144f0b8c8b64bdb75c567' 
  AND token = 'DaQnbb1oQyQWTnY53jCJlVhpjah3cjQhFgUxv6K68aI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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