SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3ebd9336a115c2930fe831a0ab0aa27ce0866918153345f8266bbae77f9d58b6' 
  AND token = 'EmGNpPVA/XU6p61VCElQlySM93eQ/eWlQmPfxsmgZWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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