SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '732078a8683351baf5b4707c73cbcad9922925d1618518daed4ad568816ff52c' 
  AND token = '9jz/SHjAApnpQ8GfCNYcF4FqT2j/UaNFApZFZbPlI8s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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