SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '404361db535b4ad0b67c793104fc7cde892f243f170cb64c1e69ca1dfaaa6602' 
  AND token = 'MDr1989MSYdQ61frgB1SK4d5v9tNPP5i0o/cmhQ6msE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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