SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5c9630c2dce93de2819648c821822bef85f0f11ed1ac243846cf87ab3469f3' 
  AND token = 'KF2Rb1OwQpJ7PdHuayFV6l1jQNq+JxQnBiJqXjHq9MI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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