SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '27a35fe91b9753e97b4f1d2a5827f7a2340d5600dc4314df60873be7064166d6' 
  AND token = 'QvMIy69vV6jJ6D1++6bEE3SpYS6fJVn86Up4Hg7tVvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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