SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd742ed30773422022e2a0568adf9cc90dfb1ff12c91617c4c8e71d2a84e6af38' 
  AND token = 'uVAUfaV6RYm+IDCj9tEnJM7SdfPSxCQeOVjN1mbxOxE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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