SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebb7a9e2d13c1d32d7e44315cdf61017129f3f5baa33f641ab5ee48fe0e1ca71' 
  AND token = 'R2EWlouQIHikzP0NBbDWlIkLBudOw1fU7EdEDpv8Tn0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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