SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f74cab06ba5275b8325d168855201b5516be4322df76a4fa17732059d4bf1e50' 
  AND token = 'GJ6xRdMTbADcIJYVrzVW48GArjibISjm8JKw9+N4x5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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