SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0847a7cbf5115865339d62c598b66bcd6bf2e54b8c0d837dd1824580177fa688' 
  AND token = 'JiE/xgcqOo8u85L8hn+19GkHXxwFPENg0/Z2r1VsS4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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