SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5ca38a27bfb5dcb67a4af82ebec36a4ceac4ca1c095a090bb43aa56c9cd495f' 
  AND token = 'IOwBZlYEQuvyIb0z1shhO/GAJndKxZ6vdfQzTyvZh6A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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