SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a569f8b02ef4ed6e0643417deab5fd4d5834f999add39110a1a0c9e87182395' 
  AND token = 'jYk7TzcyBeckqNoF66N9HeJfgRqEEOeyEuKnyE5pud8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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