SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '157c790806eb82acd2a8c7b13fbcbe7d22abf1f45708ea37144b8d2b379c4e43' 
  AND token = 'nXF0QqX3C1Os2GlYLUm/HuticYUVwl56yDjvKaOBpts=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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