SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bf811e21cdc1a035ca38ebd368fefb1193e616b769f988a00e984f3117e0a8be' 
  AND token = 'kLBmJRqyu7EM0OqS35kKG2hR4lHmdYEUkr618mqJgGE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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