SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9c243dbb2f31d706ceaa62a97beda24242ed0f4911076743c866b4e98284ab91' 
  AND token = 'Y0AubV+WkWSHijzMkQFOm4qyxb7VjoGt5XpoxedzXHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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