SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6283ae042fafb4d71cccdeae97de3e605dfd963d29338137ba0d1cbaf6208c80' 
  AND token = 'AckckeikgEXv6d4A5H56QmIbnOUxLUplW1ZMWQLwnDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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