SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd4bc47631a9c5f243bc6eef845a8f8780a64bb3280ef53098466377007c0f61' 
  AND token = '5/gA1Dgn2I9iVIZJC5n7mLI1KqgBBWUHsvykwm1CpZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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