SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0632d90bf466b62053db6bc8e3689709e8f2a30883059db0abbce73f6bf49cf' 
  AND token = '831GHMJODZMKTzkgvn99xmzTBDMSCAyMzVktGdeyOWE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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