SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ef707c55555a48b1900e99144b687faf4a11dd33ad1ea5ee6e9a2b828f98f707' 
  AND token = 'J4Ujmg7Ah6RLms5TQ8QvJdEZWG55GnPFA6kQjbCPR94=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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