SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8bf8a8166369871734723d83796cc2bd5cd482adaba99360ca09ddfa70317b3a' 
  AND token = 'Rb1mDcAOqJePj4NmTsQ+nki+ORkfoCYrzSdzDcpgm3I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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