SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd28454aaffd1f16212ecaa55bfea2a701de984450a6b18a1b1b952f52c6a3ff6' 
  AND token = 'OPWunIskghNvZpqJL2ESvhUP/IoaTswLwih0mPlraZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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