SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a2f35c12348009e423d55c1c0046293a02c88c3a9c011b52a460a5db8ff187dd' 
  AND token = 'BN55KfI9a+M/QO8BQRD5pmVHt0oMNXkAAcmSJ8ILWzo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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