SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b0f5518735f9be2bd20a2a239851a7d4a97fe7c5d0a8e2d5aa831e8f7bd5d955' 
  AND token = 'QqD00KOxLNPfc/eZ4MzraXtT18i9Y0xMXiKEFyDdv9I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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