SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '961f2f2a73fb58618c78fa979e6839e07d930587e4a54dcf59ef124dc05deffc' 
  AND token = '1XvP/ESLeAsH7tIXMxLwE2cYrnWgUuga/GrTvPDMYlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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