SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9dab9601217f2d10bb3b0f28d483e0d0b805292b0320db6d7c33dc3dc7370ee' 
  AND token = 'C7xHCNWqnd8nTZ9xZmXPe9lZ7TC28r7wWIslvIFcJTM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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