SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d7cf95af09116c1d1ccf203796d9302c833efa027e0cd56b5f079ebcad94051' 
  AND token = 'XLan9v9pCQk79ValogMgB9Lj3y/a+6tJWF+RcHpaBTs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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