SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a3b9684d3aa4a8a41de3adce465d5e7f953776082d854c800779100a9b0e966' 
  AND token = 'I1N/IzXqulwKNj9C1miYwXsSntDvEcmEe0+5wZbqywc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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