SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55266c2585a8c6b26dde3c1ab0178486ae37523bb455dcde18c32052555f2686' 
  AND token = 'XkWFjPjgwkUGkDLrrSth2zDUR52mUrM5SNdIH74cLNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}