SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '146993e83b9506b0c294fabfa2f1bfbd457d52baec24b5d5671953ad3027d0e2' 
  AND token = 'FlJGKYCA44RbnR+WwWP0slVS0vlp5rynzPtXhBcvbbw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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