SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ebfd7a0303c4754f2b24d6a7a21b3b53217241323af228b086e9bf88c06485f' 
  AND token = 'OVSVlSiXPN0SnnmUUFF8fBI51WNzUTsvmAIyeeUxpR0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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