SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1cc990ec09d88703b66bb5ed887405c16ae1ce2dbfe3f789da57ed24395a4700' 
  AND token = 'HzW1BB5iHLqtlYOg0aSHNkWld3np73lerfjgWhgfeWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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