SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20f12a34f91f9147c5e3083c05dc3ed70994a2c4620d14db289a35ce32a05fc3' 
  AND token = 'Gj8cZ4nTrLrt0jhnd2JAajopFNSeRLFYNAHS6Rf9hC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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