SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd32fac7dc48e9a2bd4c234100c6e1d7f9ed604b992d5580ed79c31de65a0a08' 
  AND token = 'dfqRw9M3Aain6aZf0C2BSOgZQSw9xOKTYS1vDhwYBTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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