SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a114f83f5a650ff7ea8203987f2a1ffbe61dc4a68b1891ebd2a45037dedd8ac' 
  AND token = 'YoNOFhKQoQTU+ZnNk9rZqOMMwd1lSQ7vPiAwgWgg8TM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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