SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e25e539f8913a483b27e872620d5710312e6da612532482189dfd8fbde937c2f' 
  AND token = '8sA8kPKhEjsGTzbsPOq4Ho5SZNh+zGt3x/g4aCupqug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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