SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cfaea46a9453baa9a9016c9398fc1c359fb48b1ec3dd7d28ab1b0221d0fecd34' 
  AND token = 'uATTQJUr3dugmCgdkYPC0QztJVZHeQ4unRKo/MzKj1c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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