SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '40196928ca008907defa78001a6009825217b2865a5da011339b8d067d3a1857' 
  AND token = 'GJI2WkkN854GYIVTTbCn7gC2JHIZfdSI53WYv/xVYog=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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