SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2bf45555c210a251b92235be06446990b9291644128ddf6d228cc8f5d92f40e' 
  AND token = 'PSCmRBS32AK4OECiMu74mr2pjrYnzgfRFy4bjVxw0q8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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