SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5c654a94b3dfa9381090f906f7a269644cad4301806e325ac792f009453cc35c' 
  AND token = 'FEO721THR87BzZuklv/YQpe6VobKgXfmKdGGGvV7q70=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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