SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd74362833ec48c91b0d05bdec1a5c38452cac31b5f7420512e587d282264000a' 
  AND token = '3YeDSZLRqBg/w6E8IACIRLVJVOKMZH3FwNpHKxLGP+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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