SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08c4b9e4e223d294161324b1808032e06860d65a04992094798b158e33b5a991' 
  AND token = 'pmNcYO1Gw2/KWiycriKSGl7WuPXWnX4WxcOcXoMMQy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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