SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a1f7b8a378fbeaccf25e944b6f52bbbf038392f960285c237ffd2078cc49a71' 
  AND token = 'kO9e/vWyeM0dgkMAydIh+qw16loQutpgwJjOnypr418=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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