SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae666fe2996a9339203aedc6fc74b08c0a9a23ffa683e633239adddb55f7e611' 
  AND token = 'YowYGtxeponcdDI5NYUZpkQ82C6meE/RN3aKRG2us6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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