SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ec668c7d70f3163ef6551246fb49390bcb183f417ca4b5e69c48d49111b12f12' 
  AND token = 'vzducujdxrMCffCwpfoiIbt6jTGUDzDA5vMVR0+76Ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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