SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2af4a8137bc3d5fe86486a32d3ffc5fabbd611a1e48fa92952b528385a421ee3' 
  AND token = 'Zsspffl+JyoUnKUjOO+wPb5DicrBRnFWj09MjZBRLKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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