SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c40cfac1d36acf708c12ddcb8f76458b3378f99436542d83f93dbb6190ca86de' 
  AND token = '5aS7iAIQjy/2ThQ2ujRYVjidn0/KPV9JGLgc1Xg/ZnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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