SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aff28b05326a66d96f4723429ae2de348020de0767fdbea8cbebeb21012bfc89' 
  AND token = 'XwT5ANhwdYeWCYD0tVCuxf8+NajTctRbliM7GDKTFyk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

JSON explain

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