SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '128ca4be00c8a1167940a5b5aaddde31cf1c787ba59ad2d100d7206836442998' 
  AND token = 'JjM8i4GThWnfu380yRq3FfI7pGWBzgr0YcUgGx4XAUk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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