SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3cde6545e9284e2bbb38773bc786df2526b8ba7d48d7cb4d3937cca28bfc69d' 
  AND token = 'HIk6pMPQz5ImGeS2b3zW2giDckryip62+uSj7O80TU4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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