SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0cddc427773c8d345d0a291f6e75f95003bc47f0694a7b5ffdcbea6147897789' 
  AND token = 'MevAIqHpPEXE3GfvgzqOvKZ76AxeHX8hB6JvkdV3pzY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

JSON explain

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