SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '170db3547339d504586c340b18320718b749a5b9b4bf4b7da1cf666f4e50efa0' 
  AND token = 'K+j+i6dCHTrqIUH/RB1t9KMslZWhbSQAAY+gpoLXrpI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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