SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fa9e7af2ed75638ad93bfe26cacfdf8e5300f439508d1ad4aaf81b3107767905' 
  AND token = 'Q4yTYUBfVfdMl45ymV1olw6SLm7hzUfGG1OjtWBFoH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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