SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '086bfa464abac415c4c37239ea1c7c236e19a301ce9fb786040462f441350f28' 
  AND token = 'va7byDgwcA7lWLkaSDC3fPVSvwh78uceK5bBGfrBs6M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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