SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dd31490295f1b55d4ea852dac9d54731e1f61cf3e1745f242ace8da9acce571' 
  AND token = 'ivGDYbPYt20VsNYjQIPnRENSXhNyJwc5p7mD1QHxaI4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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