SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4fd89993bf63e8b398c28fd8fbd14e69a7f4a571e0f94b7fa43b866e7437af2f' 
  AND token = '2RFK21s5PZ/a82OJKx3hYq3gHO0TLTGV4BcW1J4aRkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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