SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0671dc48b72e5ba6581563cc9a11d629e645e4a00b52bf04d1a4f0cd97f1f83b' 
  AND token = 'guvB0BmN/WiCC3gHKBxZszhwb9DDWr7n1hu3V/bsRZs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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