SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd860ed9a7164432a416478eb1a5d59c63af2c44bb747cb9fbfa6340d23312252' 
  AND token = 'iOFRMyQjrwOzzCYZ6Ud9N5MTOJRwyMGv6ssRRbEb8vA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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