SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98655452f3ee5ebc46f5640937a2fedc1582f176f4c9aad4247182ee29400d9c' 
  AND token = 'jfkKv+3sHnejWplFNLUHnqBcG+MADS9WuiAwWhTLCh4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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