SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14503749818d177e3f91fdce5aad6320111b2c37554bf9dbbb0a0cac24739c58' 
  AND token = 'u0lFmE2KuZz9ZICJwh5oleBllSVJTZN+7KRLTzzUPSE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}