SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '252b1cc9cc65b1e6b55f29bf237da120856e37d3ad7f0da8f6430f0b7ccb9799' 
  AND token = 'FSeYGA0O/EE7nqzM3JpCZXHZNnhOVv8puC5w4RTVpK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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