SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6331439728427b7711835d7e10549c0967728a01b02195bebe2d8cf3ba4b8dff' 
  AND token = 'ev+3X2m5Mu8j6dSpt+CYarNSicwr5m8KqxyhevkFeDw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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