SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ac8401690ae80802190643cdc53bef832d4f273bf1807543aa09b55ac8db574' 
  AND token = '7hNXd0yPCoUDi9rlLipNoOF4oHseuLqfmofb2FhoDQ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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