SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '92a136d3a999b53f9d58915f2f017874c17992e38c29bab12709a69e2a927a19' 
  AND token = 'T7PWV/LVp/vWJgSZp+XG+eOsM562zkFl+AEv/m8whP4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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