SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5aabde69690b13b70d6e507faa2aea3e727d872561d774e6a8dd1fc970caa51a' 
  AND token = 'oo0IzjrE68V2IAr7V/+hvX0bLtfjP9a0cg4yw2YI2XI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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